Pump for liquid cooling system

ABSTRACT

A pump includes a base ( 10 ), a case ( 20 ) fixed on the base, a stator ( 30 ) embedded into the case, a rotor unit ( 40 ) sandwiched between the base and the case. The rotor unit includes an inner rotor ( 42 ) surrounded by the stator and an outer rotor ( 44 ) surrounding the stator. Magnetic fields produced by the stator have interior parts interacting with the inner rotor, and exterior parts interlinking with the outer rotor. Therefore, the magnetic fields are able to be utilized sufficiently to drive the rotor unit to have a high speed rotation, and an operation efficiency of the pump is enhanced accordingly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pump, and more particularly to a pump incorporating a pair of rotors for raising an operating efficiency thereof.

2. Description of related art

With continuing development of the computer technology, electronic packages such as the CPUs are generating more and more heat that is required to be dissipated immediately. The conventional heat dissipating devices such as combined heat sinks and fans are not competent for dissipating so much heat any more. Liquid cooling systems have thus been increasingly used in computer technology to cool these electronic packages.

A typical liquid cooling system comprises a heat absorbing unit for absorbing heat from a heat source, and a heat dissipating unit which is filled with liquid. The liquid conducts heat exchange with the heat absorbing unit, thereby taking away the heat of the heat absorbing unit when the liquid is circulated. Typically, a miniature pump is used to circulate the liquid in the liquid cooling system.

A conventional pump comprises a stator secured in a case, and a rotor rotatably mounted in the case and enclosing the stator. When an electric current is delivered to armature coils of the stator, a magnetic field is produced from the stator, and interacts with another magnetic field generated by a permanent magnetic sleeve of the rotor to repulse and attract the permanent magnetic sleeve, whereby the rotor is driven to rotate.

The magnetic field produced by the stator simultaneously distributes at an interior and an exterior of the stator. However, only the exterior part of the magnetic field can interact with the another magnetic field produced by the rotor, which results in the interior part of the magnetic field being wasted. The magnetic field being not able to be utilized sufficiently causes an operating efficiency of the pump limited.

What is needed, therefore, is a pump which can overcome the above-mentioned disadvantage.

SUMMARY OF THE INVENTION

A pump includes a base, a case fixed on the base, a stator embedded into the case, a rotor unit sandwiched between the base and the case. The rotor unit includes an inner rotor surrounded by the stator, and an outer rotor surrounding the stator. Magnetic fields produced by the stator have interior parts interacting with the inner rotor and exterior parts interlinking with the outer rotor. Therefore, the magnetic fields are able to be utilized sufficiently to drive the rotor unit to have a high speed rotation, and an operation efficiency of the pump is enhanced accordingly.

Other advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present apparatus can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present apparatus. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an assembled, isometric view of a pump in accordance with a preferred embodiment of the present invention;

FIG. 2 is an exploded view of FIG. 1;

FIG. 3 is a view similar to FIG. 1 with a cover and a printed circuit board being removed for clarity;

FIG. 4 is a vertical sectional view of FIG.1;

FIG. 5 is a view of an operation principle of the pump of FIG. 1; and

FIG. 6 is a view of an operation principle of a pump in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, a pump in accordance with a preferred embodiment of the present invention is used in a liquid cooling system (not shown) for driving liquid to flow. The pump comprises a base 10, a case 20 fixed on the base 10, a stator 30 embedded in the case 20, and a rotor unit 40 rotatably received into the case 20 with an inner rotor 42 and an outer rotor 44 thereof sandwiching the stator 30 therebetween.

The base 10 has a substantially square shape with an upright, circular hole 12 defined in a central area from a top to a bottom thereof. A first pipe 14 and a second pipe 16 (seen in FIG. 3) are formed horizontally and outwardly from a sidewall (not labeled) of the base 10, wherein the first pipe 14 is located at an upper portion of the base 10, and the second pipe 16 is located at a lower portion of the base 10. Each of the first pipe 14 and the second pipe 16 has a perforation 140, 160 communicating with the circular hole 12 for allowing the first pipe 14 to function as a water-inlet, and the second pipe 16 to act as a water-outlet. An annular step 18 is formed at a middle of a height of the base 10 and around an inner circumference of the base 10 for supporting an annulus 70 thereon.

The case 20 is fixed on the base 10 by bringing four screws (not shown) to extend four corners of the case 20 and be threadedly engaged in the base 10. A ring pad 80 is disposed between the case 20 and the base 10 for preventing a liquid leakage from occurring. The case 20 also has a square configuration that has a cross-section identical to that of the base 10. An annular area of a top face of the case 20 is concaved downwardly to form a cylindrical post 220 in a center of the case 20, and a first cavity 22 surrounding the cylindrical post 220 for receiving the stator 30 therein. A plurality of areas of a bottom face of the case 20 is concaved upwardly to form a second cavity 24, a third cavity 26, and a forth cavity 28 (illustrated in FIG. 4), all of which are coaxial with the first cavity 22, wherein the second cavity 24 has a circular shape, the third cavity 26 and the forth cavity 28 have annular shapes, respectively. The second cavity 24 is enclosed by the first cavity 22, and the third cavity 26 is surrounded by the forth cavity 28 and surrounds the first cavity 22. The first cavity 22 has an opening (not labeled) oriented upwardly, the second cavity 24, the third cavity 26, and the forth cavity 28 have openings (not labeled) oriented downwardly, in other words, an interior of the case 20 is divided into two separated spaces by an interlayer (not labeled), for preventing the liquid from penetrating into the first cavity 22, and ensuring the stator 30 to be isolating from the liquid, as the pump is in operation. A height of the cylindrical post 220 is less than other parts of the base 20, whereby a printed circuit board 50 is able to be received in the first cavity 22 with a top face of the cylindrical post 220 being coplanar with a top face of the printed circuit board 50 (shown in FIG. 4). A groove 222 is defined at the top face of the case 20 and communicates with the first cavity 22 for allowing power cords (not labeled) of the printed circuit board 50 therethrough.

Also referring to FIG. 4, the rotor unit 40 is sandwiched between the case 20 and the base 10. The rotor unit 40 comprises a circular panel 400, a plurality of blades 402 raidally attached on a bottom face of the circular panel 400, a pair of inner coaxial sidewalls 404 extending upwardly and vertically from a top face of the circular panel 400, a pair of outer coaxial sidewalls 406 extending upwardly and vertically from the top face of the circular panel 400 and enclosing the pair of inner coaxial sidewalls 404, and a shaft 408 extending upwardly and perpendicularly from the top face of the circular panel 400 and enclosed by the pair of inner coaxial sidewalls 404. The plurality of blades 402 is for being received in the circular hole 12 of the base 10 and located above the annulus 70, and agitating the liquid that enters into the pump via the first pipe 14, whereby the liquid is driven to flow in a downwardly volute manner through a hole 700 of the annulus 70, and to be expelled out of the pump via the second pipe 16. An inner rotor 42 and an outer rotor 44 are sandwiched between the pair of inner coaxial sidewalls 404 and the pair of outer coaxial sidewalls 406, respectively. In the preferred embodiment of the present invention, the inner rotor 42 and the outer rotor 44 act as an inner permanent magnetic sleeve 42 and an outer permanent magnetic sleeve 44, respectively. Also shown in FIG. 5, each of the inner permanent magnetic sleeve 42 and the outer permanent magnetic sleeve 44 has alternating N and S magnetic poles 420, 422, 440, 442 distributed evenly thereon, wherein each of the N magnetic poles 422, 440 is located adjacent to each of the S magnetic poles 420, 442 and has an angular width of 360/N degrees (N is a total number of the N and S magnetic poles 420, 422, 440, 442 of each of the inner permanent magnetic sleeve 42 and the outer inner permanent magnetic sleeve 44). Each of the N magnetic poles 422 of the inner permanent magnetic sleeve 42 faces each of the S magnetic poles 442 of the outer permanent magnetic sleeve 44, and each of the S magnetic poles 420 of the inner permanent magnetic sleeve 42 confronts each of the N magnetic poles 440 of the outer permanent magnetic sleeve 44, that is to say, the poles 440, 442 of the outer permanent sleeve 44 and the poles 420, 422 of the inner permanent sleeve 42 in face-to-face relationship have opposite polarities. A bearing 46 is sleeved onto the shaft 408 of the rotor unit 40 for supporting the rotor unit 40 when the bearing 46 is accommodated in the second cavity 24 of the case 20, with the pair of inner coaxial sidewalls 404 received in the third cavity 26 of the case 20, and the pair of outer coaxial sidewalls 406 received in the forth cavity 28 of the case 20.

Shown in FIGS. 3-4, the stator 30 is for being received in the first cavity 22 of the case 20. The stator 30 comprises a plurality of yokes 32 stacked with each other, a plurality of teeth 34 extending inwardly from and equidistantly around inner peripheries of the plurality of yokes 32, a plurality of armature coils 36 respectively wound spirally onto necks of the plurality of teeth 34. A part of the plurality of armature coils 36 wound on each of the plurality of teeth 34 have opposite spirally wound configurations in respect to that of another part of the plurality of armature coils 36 wound on an adjacent one of the plurality of teeth 34; thus, each of the plurality of teeth 34 produces a magnetic field opposite to that produced by the adjacent one of the plurality of teeth 34. Each of the plurality of teeth 34 forms a piece 38 at an inner end thereof, which is wider than the neck of each of the plurality of teeth 34 for producing homogenous magnetic field as the plurality of armature coils 36 is energized. The pieces 38 of the stator 30 are distributed in a circumferentially, equidistantly spaced relationship around the inner peripheries of the plurality of yokes 32, and have a number identical to that of the N and S magnetic poles 420, 422, 440, 442 of each of the inner permanent magnetic sleeve 42 and the outer permanent magnetic sleeve 44 of the rotor unit 40. The stator 30 is received in the first cavity 22 of the case 20 and around the cylindrical post 220 with outer circumferences of the plurality of yokes 32 thereof abutting against an outer rim of the first cavity 22, inner faces of the pieces 38 thereof contacting an inner periphery of the first cavity 22.

The printed circuit board 50 is disposed on the stator 30, with its power cords extending through the cutout 222 of the case 20, and a top of the cylindrical post 220 received into a center thereof. An exterior diameter of the printed circuit board 50 is slightly less than that of the first cavity 22 of the case 20 so that the printed circuit board 50 can be substantially accommodated therein. The printed circuit board 50 interconnects the stator 30 with a power source (not shown), for providing an alternating electric current to the stator 30.

The pump further comprises a cover 60 lying over the printed circuit board 50 and firmly coupling with the case 20 by screws. The cover 60 has a cross section identical to that of the base 10, so that when the pump is assembled to be an integral, it has a shape similar to a cube. The cover 60 is used for protecting the inner elements of the pump.

As shown in FIGS. 2, 4 and 5, in use, the alternating electric current produced by the printed circuit board 50 flows through the plurality of armature coils 36 to make the plurality of armature coils 36 generate the magnetic fields (it is called magnetic effect of electric current). Since the different spiral wound configurations of the plurality of armature coils 36 on the plurality of teeth 34, the stator 30 generates magnetic fields distributed at an interior and exterior thereof, some of which are oriented inwardly, and other of which intervening into the some of magnetic fields are oriented outwardly. Due to symmetrical constructions of the stator 30 and the rotor unit 40, only a part thereof is described as given below: when a predetermined electric current is delivered to the stator 30, one of the plurality of teeth 34 of the stator 30 is magnetized in a manner such that an inner end thereof exhibits an S polarity, and an outer end thereof exhibits an N polarity, thereby defining a first magnetic field having a radially outward orientation; the adjacent one of the plurality of teeth 34 is magnetized in a manner such that an inner end thereof exhibits an N polarity, and an outer end thereof presents an S polarity, thereby defining a second magnetic field having a radially inward orientation. An interior part of the first magnetic field interlinks with the S magnetic pole 420 of the inner permanent magnetic sleeve 42, and an exterior part of the first magnetic field interacts with the N magnetic pole 440 of the outer permanent magnetic sleeve 44, to generate first turning torques, which respectively repulse the S magnetic pole 420 of the inner permanent magnetic sleeve 42 and the N magnetic pole 440 of the outer permanent magnetic sleeve 44, to render the rotor unit 40 to have an anticlockwise rotation. An interior part of the second magnetic field interlinks with the N magnetic pole 422 of the inner permanent magnetic sleeve 42, and an exterior part of the second magnetic field interacts with the S magnetic pole 442 of the outer permanent magnetic sleeve 44, to generate second turning torques, which has orientations identical to that of the first turning torques, to respectively repulse the N magnetic pole 422 of the inner permanent magnetic sleeve 42 and the S magnetic pole 442 of the outer permanent magnetic sleeve 44, to further render rotor unit 40 to rotate anticlockwise. The alternating electric current changes its direction with a high frequency, which is synchronized with the rotation of the rotor unit 40, in order to make sure that the stator 30 changes its polarities in time, thereby to provide the inner permanent magnetic sleeve 42 and the outer permanent magnetic sleeve 44 with corresponding turning torques, which are able to drive the rotor unit 40 to rotate continuously.

Since the inner permanent magnetic sleeve 42 and the outer permanent magnetic sleeve 44 respectively located into and out of the stator 30, the interior parts and the exterior parts of the magnetic fields exerted by the stator 30 is able to be utilized sufficiently, and produce more turning torques. The more turning torques acting on the rotor unit 40 could cause the rotor unit 40 to rotor much rapidly. Therefore, a high speed rotation of the rotor unit 40 is obtained, and an operation efficiency of the pump is enhanced accordingly.

Referring to FIG. 6, it can be understood, in order to resolve a problem of “dead point”, which may cause the pump is not able to start itself, the inner permanent magnetic sleeve 42 is staggered with the outer permanent magnetic sleeve 44, to enable that a boundary of two adjacent N and S magnetic poles 420, 422 of the inner permanent magnetic sleeve 42 defines an acute angle with a corresponding intermediate line between two adjacent N and S magnetic poles 440, 442 of the outer permanent magnetic sleeve 44.

It is believed that the present invention and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention. 

1. A pump for use with a liquid cooling system, comprising: a base; a case fixed on the base; a stator embedded into the case; a rotor unit received between the case and the base, the rotor unit being separated in a liquid-isolating relationship with the stator, comprising: an inner rotor surrounded by the stator; an outer rotor surrounding the stator; and a plurality of blades attached below the inner rotor and the outer rotor for driving the liquid to flow.
 2. The pump as claimed in claim 1, wherein the rotor comprises a circular panel, the plurality of blades being fixed on a bottom of the circular panel, and the inner rotor and the outer rotor being secured on a top of the circular panel.
 3. The pump as claimed in claim 2, wherein the rotor further comprises a pair of inner coaxial sidewalls extending upwardly from the top of the circular panel and sandwiching the inner rotor therebetween, a pair of outer coaxial sidewalls extending upwardly from the top of the circular panel and sandwiching the outer rotor therebetween, and a shaft enclosed by the pair of inner coaxial sidewalls.
 4. The pump as claimed in claim 3, wherein the case defines an annular cavity having an opening oriented upwardly, the stator being received in the annular cavity.
 5. The pump as claimed in claim 4, wherein the case defines a circular cavity having an opening oriented downwardly and receiving the shaft of the rotor unit therein, an annular chamber having an opening oriented downwardly and receiving the pair of inner coaxial sidewalls of the rotor unit therein, and another annular chamber having an opening oriented downwardly and receiving the pair of outer coaxial sidewalls of the rotor unit therein.
 6. The pump as claimed in claim 5, wherein the annular cavity of the case is surrounded by the annular chamber and surrounds the circular cavity, and the another annular chamber surrounds the annular chamber.
 7. The pump as claimed in claim 5 further comprising a bearing accommodated in the circular cavity of the case for supporting the shaft of the rotor unit therein.
 8. The pump as claimed in claim 4, wherein a part of the case surrounded by the annular cavity is shorter than other parts of the case.
 9. The pump as claimed in claim 8 further comprising a printed circuit board disposed on the stator and in the annular cavity of the case, wherein a top face of the printed circuit board is coplanar with a top face of the part of the case surrounded by the annular cavity.
 10. The pump as claimed in claim 4 further comprising a cover fixed on the case to overlay the stator, cross-sectional areas of the cover, the case, and the base being equal to each other.
 11. The pump as claimed in claim 2, wherein the base defines a transverse hole in an upper portion thereof, a horizontal hole in a lower portion thereof, and an upright hole from a top to a bottom thereof, the upright hole communicating the horizontal hole with the transverse horizontal hole and receiving the plurality of blades of the rotor unit therein.
 12. The pump as claimed in claim 11 further comprising an annulus received in the upright hole and at a middle of a height of the base to separate the horizontal hole with the transverse hole of the base, wherein the rotor unit is located above the annulus.
 13. The pump as claimed in claim 1, wherein each of the inner rotor and the outer rotor has alternating N and S magnetic poles distributed evenly therearound, a number of the N and S magnetic poles of the inner rotor being essentially identical to that of the outer rotor.
 14. The pump as claimed in claim 13, wherein each of the N magnetic poles of the inner rotor faces each of the S magnetic poles of the outer rotor, both of which have an equal angular width.
 15. The pump as claimed in claim 13, wherein the magnetic poles of the inner rotor and the magnetic poles of the outer rotor in facing relationship have opposite polarities.
 16. The pump as claimed in claim 13, wherein each of the S magnetic poles of the inner rotor and each of the N magnetic poles of the outer rotor are staggered each other with an acute angle defined therebetween.
 17. The pump as claimed in claim 15, wherein the stator comprises a plurality of teeth positioned in a circumferentially equidistant relationship therein, a number of the teeth is identical to the number of the S and N magnetic poles of the inner rotor.
 18. A liquid pump, comprising: a casing defining therein a chamber, an inlet and an outlet both being in flow communication with the chamber; a rotor received in the chamber and being rotatable to drive liquid to enter the chamber via the inlet and to exit the chamber via the outlet, the rotor comprising a cylindrical outer wall, a cylindrical inner wall and a substrate connecting with a bottom end of the outer and inner walls, an agitator being formed on a bottom surface of the substrate; an outer magnetic ring embedded in the outer wall of the rotor and an inner magnetic ring embedded in the inner wall of the rotor; a stator received in the chamber to drive the rotor to rotate; a partition seat received in the chamber and arranged between the stator and the rotor to space the stator and the rotor; and a top cover mounted to a top of the casing.
 19. The liquid pump as described in claim 18, wherein each of the outer and inner magnetic rings have a plurality of alternating N and S poles, and have different poles at opposing surfaces thereof so that a attractive force exists therebetween. 